Discordant left and right ventricular optimal atrioventricular and interventricular delays during biventricular pacemaker optimization

Echocardiography-guided optimization of atrioventricular (AV) delay (AVD) improves left ventricular (LV) filling, and optimized interventricular delay (VVD) leads to further improvement in cardiac output in patients with biventricular (Biv) pacing. Investigators use LV filling and ejection to optimize AV and VV delay in patients with Biv pacing. Effect of such optimization on right-sided hemodynamics remains unknown. In our experience, few patients experience worsening of right ventricle (RV) hemodynamics when LV parameters are optimized. We present a series of cases where we observed suboptimal RV filling or ejection at optimal AVD and VVD for LV. This RV-LV discordance may contribute to nonresponder rate to cardiac resynchronization therapy (CRT) and should be evaluated in a consecutive series of CRT nonresponder patients to help improve CRT response.